Tau induces cooperative Taxol binding to microtubules

Jennifer L. Ross, Christian D. Santangelo, Victoria Makrides, D. Kuchnir Fygenson

Research output: Contribution to journalArticle

40 Scopus citations

Abstract

Taxol and tau are two ligands that stabilize the microtubule (MT) lattice. Taxol is an anti-mitotic drug that binds β tubulin in the MT interior. Tau is a MT-associated protein that binds both α and β tubulin on the MT exterior. Both Taxol and tau reduce MT dynamics and promote tubulin polymerization. Tau alone also acts to bundle, stiffen, and space MTs. A structural study recently suggested that Taxol and tau may interact by binding to the same site. Using fluorescence recovery after photobleaching, we find that tau induces Taxol to bind MTs cooperatively depending on the tau concentration. We develop a model that correctly fits the data in the absence of tau, yields the equilibrium dissociation constant of ≈ 2 ̀M, and determines the escape rate of Taxol through one pore to be 1.7 × 103 (M·s)-1. Extension of the model yields a measure of Taxol cooperativity with a Hill coefficient of at least 15 when tau is present at a 1:1 molar ratio with tubulin.

Original languageEnglish (US)
Pages (from-to)12910-12915
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume101
Issue number35
DOIs
StatePublished - Aug 31 2004

ASJC Scopus subject areas

  • General

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